Method of molding articles



Aug. `es, 1935.

w. s. HOPKIN METHOD OF MOLDING ARTICLES Filed Aug. 26, 1950 2 Sheets-Sheet l HHH nn Aug- 6, 1935- W. s. HOPKIN 2,010,669

METHODOF MOLDING ARTICLES n Filed Aug. 26, 1950 2 Sheets-Sheet `2 '3/ mim W W um Patented Aug. 6, l1935 Y 2,0,66

7' f UNITED lsfrArEs uPATErrr oFFIc e, f

WalterS. lilopkin,` Oak Park, Ill., assigner-to Western Electric Ccrnpany, Incorporated, New York, N. Y., a corporation of New York ApplicationAugust 26, 1930, Serial No. 417,827

claims. (o1. 18-f55) This invention relates to a method of and ap- Fig. r6 is a Vperspective view of the Acompleted paratus for molding articles, and more particu- Subset cover. Y f larly to a method of and apparatus for molding Referring now to the drawings in which like refcomposite articles from phenol plastic materials. 'erence'numerals designate similar parts through- 5 An object of this invention is to provide a simout the several views thereV is disclosed a pairfof 5 ple and4 eiiicient method `of and apparatus for complementary upper' and lower*multi-compafifjg'f accurately producing articles from plastic moldment molding members or dies II), and II which ing materials. A. are suitably designed and shaped tomold from Inaccordance with this object as `applied to the powdered phenoliccondensation productor ,other` 10 manufacture oftelephone subset covers one emthermosetting molding material y placed in the 10 bodment of the invention includes a pair of comlower molding member I I,at asingle operation` a plementary, upper and lower-molding members plurality of telephone subset covers I2 shown in or dies which formrespectively the inner and Fig. 6. The upper molding memberl hasproouter surfaces of the subsetcover. Pins in two jecting portions while the inner surfaces of the i5 diagonally opposite corners of one member encover I2, and the lower molding member II has l5 gaging elongated receiving apertures in the other `Cavities` to form the outer.V surfaces Qf Ltllese member which haveV their axes disposed in the dicovers. These molding members are made to en; rection of aline running through acenter guide gage each other properly by means of round `cen- .A pin, thus allowing for unequalexpansion in the tral and' cornerrguide pins I3 provided inrthe two molding members in the heating and cooling upper member IU which Iit within 'correspond- 20 thereof Vserve to guide the two molding members. ingly positioned apertures in the lower molding Perforations or gong slots are formed in the side member II. A pair of these diagonally opposite walls of the produced cover by means of movapertures I4 (Fig. 2) [are elongated or extended e able insertsmounted in the lower moldingmem in the form` of an ellipse along a diagonal `line n ber and operated by cams actuated upon opening running through the-.center guide apertures .so 25 and closure ofthe molding members. Pins loosely that the pins' I -3` engaging these apertures ,may mounted in the lower molding member produce move radially outwardly or inwardly upon rela- Yscrew apertures in the cover and serve to eject tive Yexpansion or contraction of ione! molding v the finished cover` upon themovement of an ejecmember withrespect to the other due to their tor plate. A templet having bulged or curved unequal heating or cooling. Thus these elongated 30 edge surfaces serves to set the molded cover for diagonally opposite guide apertures I4 allow for a time during cooling, so that when. the cover is relative radial expansion in the molding members completely cooled its sides will be straight. but do not permit relativerotation therebetween Copending applications Serial Nos. 324,812 and because the pins snugly engage the sides ,of the 324,863, both led `December l0, 1928, show a apertures Mgandby reason .of such an arrangef 35 molding press in which the molding members mentand because the central pin I3 is made to may be usedand reference to these copending tits aperture snugly the walls of the cover I 2 applications is made for more complete informer DlOdllCcd by each COmDaFtmeIl' Of the H1016 are 0f tion on the press structure. the'- same thickness throughout and a uniform 40 "A clear understanding of the invention may be product is produced. vThe other two pins I3 at the 4o had from the following detailed description of Aupper right 'andzlowerrleft hand. corners (Fig. 2) this `one embodiment and the accompanying are not used-,foraligning purposes and do not drawings thereof, wherein Y snugly engage their apertures but are simply used e Fig. 1 is a fragmentary side View of the moldto raise the upper molding memberI II) fromvthe s ing press with which the molding apparatusis lower moldingmember I I in the ejecting process 45' preferably fused, Y which will be` described later. 7

Fig.,`2. is a plan view, taken on the line`2-2 of The gong slots or perforations` I5 in the end Fig. .li of the upper and lower molding members, 4of the cover member I2 areformed by movable l 3 isa sectional View of the upper and lower horizontal inserts .or cores, I6 mounted in the molding members, taken on the line V3-3 of Fig. 2, lower` molding member II around the end of each 50 andshowing an ejector plate positioned beneath mold compartment and which are reciprocated the lower. molding member, into and out of the mold cavity by vertically dis- .FigJl is an end View of the templet upon which posed blankv like Vcams I'I. Each of the cams is the formed covers are cooled, provided with a central camming or angular por- Fig. 5 is a plan view of the templet, and tion I8 which engages a correspondingly cammed 55 aperture I9 of each insert I6, as clearly appears in the case of one such insert located at the right hand end of the molding member II in Fig. 3. The upper ends of the cams I1 have individual washers or packing 20 secured therearound to prevent dust or' the powdered molding material from interfering with their operation, and the lower ends of these cams extend through apertures in a bottom cover plate 24 secured to the molding member II.

An inscription or configuration 25 (Fig. 3) containing the manufacturers name is formed in one end of each mold compartment of the molding member II to impress a corresponding configuration 2B in the end of each molded cover I2. A pair of upright pins 21 for forming a screw aperture 28 in each side of the cover I2 are loosely or removably supported in each lower mold compartment by means of lower inverted cone shaped ends 29 thereof engaging corresponding recesses in the lower molding member II, and these cone shaped ends terminate adjacent to apertures 30 provided in the bottom plate 24 for receiving ejecting mechanism, as will appear presently, to eject the pins 21. Apertures 3l are provided in the upper molding member I0 for receiving the pins 21 upon the closure of the molding members I0 and Il in the molding process.

In order to eject the molded covers I2 an ejector plate 32 is provided beneath the lower molding member II and has pins 33 for piercing through apertures in the molding member II and engaging the guide pins I3 of the upper molding member I0 to raise the molding member I0 out of engagement with the lower molding member Il. Pins 34 are provided on the ejector plate 32 directly below the lower ends of the cams I1 to raise these cams when the ejector plate is moved upwardly, thereby moving the inserts I6 out of the mold cavities, and pins 35 extend upwardly from the ejector plate 32 for engaging the lower ends of the movable pins 21 to raise these pins and thereby eject the covers I2 from the mold at the time that the inserts IB have been moved outwardly, as just described.

The molding members IB and II and the ejector plate 32 may be operated by means of various types of known presses, and in the operation the molding member I Il is first withdrawn upwardly from the lower molding member II, and the pins 21 are'inserted in position in the molding member II by hand. The powdered phenolic material or other molding material is then manually deposited and distributed in the various molding compartments in the lower molding member II and the molding member I!) is then brought down into engagement with molding member II, the guide pins I3 effecting an accurate alignment therebetween, as aforedescribed. Whenthe members I0 and II close upon each other the member I0 engages the top ends of the cams I1 and thereby forces the inserts I 6 inwardly to form the slots l5 in each cover I2 formed by the molding members.

The molding members I0 and II are now subjected to heat and pressure to mold the covers I2, and next the members I0 and II are cooled by exposing them to cooling platens to complete the curing operation and to shrink the covers free of the walls of the molds, thereby producing the configuration or inscription 26 in one end of the cover. Then the ejector plate 32 is moved underneath the molding member I l and raised so that the pinsl 33 engage the guide pins I3, thereby separating the molding members. At this time the pins 34 of the ejector plate also engage and raise the cams I1 to move or withdraw the inserts I 6 out of the mold cavities, and the pins 35 engage the lower ends of the screw aperture forming pins 21 to move the latter pins upwardly to raise thereby the molded covers I2 a slight distance out of the compartments of the molding member II. The covers I2 with the pins 21 adhering thereto are then, after the molding member IG is secured clear of the molding member II, manually removed from the molding member II. Before another set of covers are molded the molding members I@ and II are brought into engagement with each other to move the cams I1, which will be projecting a slight distance upwardly from the molding member I I, downwardly to move the inserts I6 inwardly in the molding position. Then the molding members IB and II are again separated, and are made ready for another molding operation by inserting the. pins 21 in the member II as mentioned above.

The preferable press for operating the molding members IG and Il, and the ejector plate 32 inthe above described manner is the one described in detail in the aforementioned copending applications Serial Nos. 324,812 and 324,863 and shown in side elevation in Fig. 1. This type of press is double acting in that two sets of the pairs of molding members I0 and II are carried by a rotatable table 39, and while the set at the right hand side is subjected to heating and pressing platens 4il-40 to mold the covers I2, the set Ill and I I at the left hand side is subjected to cooling platens II-4I, or exposed to the ejector plate 32 which may be inserted above the lower platen 4I .which is adapted to raise said ejector plate into engagement with the molding members to separate them as above described, and eject the molded covers. A tiltable head 42 provided with latches 43-43 maintains the upper and the lower molding members IIJ and II separatedduring the ejecting and filling operations.

While the molded covers I2 are being removed from the lower molding member II the pins 21 remain clinging to them, and these` pins are manually removed from the covers and the covers I2 are inverted by hand and have their rims or brims inserted over templets 44 arranged in multiple in an elevated manner on a common base plate 45, one of these templets appearing in Figs. 4 and 5. Each templet 44 has convex or bulged side and end surfaces 46-46 and 41--41 which cause the rims of the cover vI 2 to bulge outwardly upon cooling and shrinking around the templet. After this setting over the templets the covers are removed therefrom and allowed to cool completely, when their sidesY or walls become exactly straight and will accurately fit the mounting member to which they are later to be applied. The walls of the coversof their own accord would tend to shrink concavely or warp inwardly, but by giving them this preliminary outward set when they become thoroughly cool their walls are exactly straight.

Therefore it is believed to be -apparent from the foregoing description that the molding apparatus herein disclosed accurately and efficiently produces the cover members which it is designed to construct. Although one specic embodiment of the invention has been described indetail, it will of course be understoodv that the invention is not to be limited thereto but is to apply to the scope of the appended claims.

What is claimed is:

1. A method of molding moldable material of a kind which tends to warp during cooling, subjecting the material to heat and pressure in a mold, removing the molded article from the mold, and giving the article a predetermined set during initial cooling to compensate for distortion during iinal cooling.

2. A method of molding moldable material of a kind which tends to warp during cooling, subjecting the material to heat and pressure in a mold, removing the molded article from the mold, and giving an outwardly bulging set to the walls of the article during initial cooling whereby the walls become straight onA final cooling.

3. A method ofy molding moldable material of a `kind which tends to warp during cooling, subjecting the material to heatv and pressure in a mold, removing the molded articlefrom the mold, placing the removed article upon a templet to effect a convexly curved shape in the walls of the material during initialV cooling and removing the article from the templet during iinal cooling.

4. A method of molding moldable material of a kind which tends to warp during cooling, molding the material, later setting the molded material over a templet, initially cooling the material to cause it to assume a shape opposite to the shape which the material would naturally assume, removing the material from the templet and iinally cooling the material to assume a nal form.

5. The method of molding multisided hollow articles which comprises placing in a mold under heatand pressure a moldable material of a kind which tends towarp when cooling, removing the article from the mold, applying a force to bend a. wall ofthe article outwardly, cooling the article for a period while maintaining said wall in said bent position, removing the restraint from said wall and cooling the article for a further 20 interval.

WALTER S. HOPKIN. 

